Everything is made up of tiny particles often called atoms. However, there are other types of particles like subatomic particles (which make atoms up) called protons, neutrons and electrons.

MoleculeA molecule is 2 or more atoms which are bonded together.

ElementsElements are substances that can be found on the periodic table. They are made atoms of the same kind with no other types of atoms with them. There are over 100 elements and new ones are being discovered. An element can be an individual atom or several bonded atoms.

CompoundsA compound is a substance containing two or more different atoms that are chemically bonded together.

MixturesA mixture are a mix of two or more types of atoms/molecules that are not chemically joined

SymbolsChemicals are shown by symbols. They are abbreviations of the full word as it tends to be long. E.g. Mg is for magnesium. Their symbols can be found on the periodic table.

SolutionsSoluble substances (solutes) are substances that can be dissolved. These are mixed with a solvent (a liquid that can dissolve solutes) to make a solution which is the final substance.

The States of MatterSolids, Liquids and Gases are the three states of matter. They contain different properties:

SolidsThe atoms in solids are regularly arranged and are very compact. Solids therefore have a fixed shape and volume and cannot flow. They also can't be compressed (beyond a ridiculously slight amount).

LiquidsTheses atoms are also compact but not as compact and can move around each other. They therefore change shape to fill the container and can flow but they have a fixed volume. They also can't be compressed much.

GasesThese atoms are not compact and move around a lot, filling their container and sometimes bumping into each other. They can also flow and can be compressed.

Changing StatesSome changes of state are caused by lack of kinetic energy, caused by lack of thermal energy often called 'cooling down.' As these substances lose heat, and get to certain temperatures, they change state...Condensation - gas to liquidFreezing - liquid to solidDeposition - gas to solid

Other changes of state are caused by gain of kinetic energy, caused by gin of thermal energy (heating). As substances gain heat, and get to certain temperatures, they change state...Melting - solid to liquidEvaporating - liquid to gasSublimation - solid to gas

Diffusion and DilutionDiffusion is when substances naturally mix because of the continuously moving particles: atoms move from areas of higher concentration to areas of lower concentration till they reach a state of equilibrium (equal density of atoms) It’s faster in gases than in liquids and doesn't happen in solids.​Dilution is making a liquid weaker. An example of this is when squash is mixed with water.